Field of the Disclosure
The technology of the disclosure relates to power units for providing power to remote antenna units in a distributed antenna system.
Technical Background
Wireless communication is rapidly growing, with ever-increasing demands for high-speed mobile data communication. As an example, so-called “wireless fidelity” or “WiFi” systems and wireless local area networks (WLANs) are being deployed in many different types of areas (e.g., coffee shops, airports, libraries, etc.). Distributed communications or antenna systems communicate with wireless devices called “clients,” which must reside within the wireless range or “cell coverage area” in order to communicate with an access point device.
One approach to deploying a distributed antenna system involves the use of radio frequency (RF) antenna coverage areas, also referred to as “antenna coverage areas.” Antenna coverage areas can have a radius in the range from a few meters up to twenty meters as an example. Combining a number of access point devices creates an array of antenna coverage areas. Because the antenna coverage areas each cover small areas, there are typically only a few users (clients) per antenna coverage area. This allows for minimizing the amount of RF bandwidth shared among the wireless system users. It may be desirable to provide antenna coverage areas in a building or other facility to provide distributed antenna system access to clients within the building or facility. However, it may be desirable to employ optical fiber to distribute communication signals. Benefits of optical fiber include increased bandwidth.
One type of distributed antenna system for creating antenna coverage areas includes distribution of RF communications signals over an electrical conductor medium, such as coaxial cable or twisted pair wiring. Another type of distributed antenna system for creating antenna coverage areas, called “Radio-over-Fiber” or “RoF,” utilizes RF communications signals sent over optical fibers. Both types of systems can include head-end equipment coupled to a plurality of remote antenna units (RAUs) that each provides antenna coverage areas. The RAUs can each include RF transceivers coupled to an antenna to transmit RF communications signals wirelessly, wherein the RAUs are coupled to the head-end equipment via the communication medium. The RF transceivers in the remote antenna units are transparent to the RF communications signals. The antennas in the RAUs also receive RF signals (i.e., electromagnetic radiation) from clients in the antenna coverage area. The RF signals are then sent over the communication medium to the head-end equipment. In optical fiber or RoF distributed antenna systems, the RAUs convert incoming optical RF signals from an optical fiber downlink to electrical RF signals via optical-to-electrical (O/E) converters, which are then passed to the RF transceiver. The RAUs also convert received electrical RF communications signals from clients via the antennas to optical RF communications signals via electrical-to-optical (E/O) converters. The optical RF signals are then sent over an optical fiber uplink to the head-end equipment.
The RAUs contain power-consuming components, such as the RF transceiver, to transmit and receive RF communications signals and thus require power to operate. In the situation of an optical fiber-based distributed antenna system, the RAUs may contain O/E and E/O converters that also require power to operate. As an example, the RAU may contain a housing that includes a power supply to provide power to the RAUs locally at the RAU. The power supply may be configured to be connected to a power source, such as an alternating current (AC) power source, and convert AC power into a direct current (DC) power signal. Alternatively, power may be provided to the RAUs from remote power supplies. The remote power suppliers may be configured to provide power to multiple RAUs. It may be desirable to provide these power supplies in modular units or devices that may be easily inserted or removed from a housing to provide power. Providing modular power distribution modules allows power to more easily be configured as needed for the distributed antenna system. For example, a remotely located power unit may be provided that contains a plurality of ports or slots to allow a plurality of power distribution modules to be inserted therein. The power unit may have ports that allow the power to be provided over an electrical conductor medium to the RAUs. Thus, when a power distribution module is inserted in the power unit in a port or slot that corresponds to a given RAU, power from the power distribution module is supplied to the RAU.
It may be desired to allow these power distribution modules to be inserted and removed from the power unit without deactivating other power distribution modules providing power to other RAUs. If power to the power unit were required to be deactivated, RF communications for all RAUs that receiver power from the power unit may be disabled, even if the power distribution module inserted and/or removed from the power unit is configured to supply power to only a subset of the RAUs receiving power from the power unit. However, inserting and removing power distribution modules in a power unit while power is active and being provided in the power unit may cause electrical arcing and electrical contact erosion that can damage the power distribution module or power-consuming components connected to the power distribution module.